In the manufacture of crankshafts it is necessary to measure main bearings of the crankshaft, which define a main axis of rotation of the crankshaft, as well as crank bearings on crank pins which are situated eccentrically with respect to the main axis of rotation. The measurement is used, for example and in particular, to check the axial runout properties of the faces of the main bearings and of the crank bearings.
For carrying out the necessary measurements, the crankshaft is initially clamped in such a way that it is rotated about its main axis of rotation, and during the rotation of the crankshaft the faces of the main bearings are contacted, using an appropriate measuring probe. The measuring data thus obtained may be used to check whether the faces of the main bearings have the required axial runout properties.
After the measurement of the faces of the main bearings is completed, the crankshaft is rechucked in such a way that the rotational axis about which the crankshaft is rotated during the subsequent measurement is defined by the rotational axis of symmetry of a crank bearing to be measured. After the rechucking, the crankshaft is rotated about this rotational axis, and the faces of the crank bearing are contacted using a probe. Since the crank pins are situated with differing eccentricities with respect to the main axis of rotation, this operation is repeated until all crank bearings have been measured.
In this regard, it is disadvantageous that the rechucking operation is time-consuming.
A manually operable surface line test apparatus is known from DE 30 46 708 C2 which is suited in particular for crankshaft pins. The surface line test apparatus known from the cited publication is mountable on a crank pin to be tested, and may be clamped onto same by means of a clamping device.
A manually operable face measuring apparatus is known from DE 16 24 105 U, by means of which the face spacing at bearing sites on crankshafts, for example, is measurable.
A grinding center for grinding crankshafts is known from DE 10 2007 026 562 B4, in which the main bearings are ground in a first station, and two lift bearings of the crankshaft are ground in pairs in each case in a second station.
A measuring device for in-process measurement of a test piece during a machining operation on a machining unit, in particular a grinding machine, is known from DE 10 2010 035 147 A1, having a measuring head which is movable, relative to a base body of the measuring device, between a neutral position and a measuring position in which the measuring head is in measuring contact with the test piece. The measuring head is connected to the base body via a rod assembly, and during the measurement of a crank pin of a crankshaft, follows the orbital rotations thereof about a main axis of rotation which is defined by the main axis of rotation of the crankshaft.
A similar measuring device is also known from US 2003/0056386 A1.